Cultural Management

Remove symptomatic plants from your garden or greenhouse. Burn, bury or hot compost the affected plants.
Soak seeds in water at 122°F for 25 min. before sowing.
To keep leaves dry and to prevent the spread of the pathogens, avoid overhead watering and instead use a drip-tape or soakerhose.
Also to prevent spread, DO NOT handle plants when they are wet and routinely sterilize tools with either 10% bleach solution or (better) 70% alcohol (e.g., rubbing alcohol).
Consider using preventative applications of copper-based products registered for use on tomato, especially during warm, wet periods.
Keep in mind however, that if used excessively or for prolonged periods, copper may no longer control the disease.
Burn, bury or hot compost tomato debris at the end of the season
Wait at least one year before planting tomatoes in a given location again.